(i) Field of the Invention
This invention relates to a back pressure regulator and non-return valve for use in any system where gas is required to flow at a selected maximum pressure in one direction only. In one use, the back pressure regulator and non-return valve is used in a system and an apparatus for the separation of a mixture of gases and vapors into its constituent components, e.g., in the separation and recovery of oxygen from air, or in the separation and recovery of hydrogen from a hydrocarbon gas mixture.
(ii) Description of the Prior Art
As noted above, a back pressure regulator and non-return valve is useful in systems and apparatuses which have been proposed to separate a mixture of gases and vapors into its constituent components. Most such systems and apparatuses involve either complicated procedures or require the use of equipment which is expensive both to assemble and to operate. All of the systems of the prior art, including improved systems taught in Canadian Pat. No. 986,424 issued Mar. 30, 1976 to Robert A. Ritter and David G. Turnbull and in copending United States patent application Ser. No. 107,860, require a back pressure regulator and non-return valve at one or more points in the system.
One suggestion for such a back pressure regulator and non-return valve is taught in the aforementioned copending United States patent application Ser. No. 107,860 which taught a back pressure regulator and non-return valve comprising: a capped hollow plug having at least one perforation through the wall thereof; a tubular molded diaphragm disposed along the central region of the plug, the diaphragm having walls whose thickness decreases gradually from the bottom to the top thereof, the diaphragm being secured only at the bottom thereto but being selectively movable longitudinally along the capped hollow plug, to situate the diaphragm with respect to the aperture so that a selected diaphragm thickness is opposite the aperture; and means for supplying gas under pressure within the hollow plug; whereby the unsecured area of the diaphragm is urged open upon the application of a selected pressure dependent on the thickness of the diaphragm opposite the aperture, thereby to provide an annular flow passage.